1. Field of the Invention
The present invention relates to an apparatus for a display device, and more particularly, to an apparatus including a gas injector where a nozzle module is detachable.
2. Discussion of the Related Art
Flat panel display (FPD) devices having portability and low power consumption have been a subject of increasing research in the present information age. Among the various types of FPD devices, liquid crystal display (LCD) devices are commonly used in notebook and desktop computers because of their high resolution, capability of displaying colored images, and high quality image display.
In general, an LCD device includes a first substrate, a second substrate and a liquid crystal layer between the first and second substrates. The first substrate and the second substrate may be referred to as an array substrate and a color filter substrate, respectively. A gate line, a data line, a thin film transistor (TFT) and a pixel electrode are formed on the first substrate, and a color filter layer and a common electrode are formed on the second substrate. The gate line crosses the data line to define a pixel region, and the TFT is connected to the gate line and the data line. In addition, the pixel electrode connected to the TFT is formed in the pixel region.
A semiconductor device or an LCD device is fabricated by repetition of a deposition step of forming a thin film on a wafer or a glass substrate, a photolithographic step of exposing some portions of the thin film using a photosensitive material, a patterning step of removing the exposed thin film and a cleaning step of eliminating a residual material. Each step of the fabrication process is performed in a chamber of an apparatus under an optimum condition for each step.
FIG. 1 is a schematic cross-sectional view showing a plasma apparatus for a semiconductor device or a display device according to the related art. In FIG. 1, the plasma apparatus includes a chamber 10 defining a reaction space, a susceptor 20 having a substrate 30 thereon, a gas injector 40 over the susceptor 20 and a gas supply tube 80. The gas injector 40, which may be referred to as a shower head or a gas distributor, includes a plurality of injection holes 42 to distribute gases toward the susceptor 20. An upper plate 50 is disposed over the gas injector 40 and functions as a plasma electrode to apply a radio frequency (RF) power to reaction gases. The upper plate 50 is connected to an RF power supply 60, and an impedance matching box (IMB) 70 is connected between the upper plate 50 and the RF power supply 60 to maximize the RF power. The susceptor 20 is grounded to function as an opposite electrode to the plasma electrode. The RF power may be applied to the susceptor 20. An edge portion of the gas injector 40 is fixed to the upper plate 50 to define a buffer space 52. Reaction gases are supplied to the buffer space 52 through the gas supply tube 80 from an exterior gas tank (not shown) and then are primarily diffused in the buffer space 52. Accordingly, the reaction gases are uniformly injected into the chamber 10.
FIG. 2 is a schematic perspective view showing a gas injector of a plasma apparatus for a semiconductor device or a display device according to the related art. In FIG. 2, the gas injector 40 includes a plurality of injection holes 42. The gas injector 40 may be formed of aluminum (Al) and may have a size larger than a substrate. Since only the edge portion of the gas injector 40 is fixed to the chamber 10 (of FIG. 1) or the upper plate 50 (of FIG. 1), a central portion of the gas injector 40 sages under the weight. The sag of the central portion causes non-uniformity in gas distribution between the edge portion and the central portion. As the size of the gas injector 40 increases, the sag in the gas injector 40 increases. To prevent the sag in the gas injector 40, the gas injector 40 may be formed to have an increased thickness “t.” For example, the gas injector 40 may have a thickness of about 30 mm to about 35 mm in a plasma apparatus for a 1500 mm×1850 mm substrate, while the gas injector 40 may have a thickness of about 50 mm in a plasma apparatus for a 1950 mm×2250 mm substrate.
In addition, since the plurality of injection holes 42 are formed to have a density of about 11000 ea/m2, the injection holes 42 of about 35000 ea may be formed in the gas injector 40 of a plasma apparatus for a 1500 mm×1850 mm substrate and the injection holes 42 of about 50000 ea may be formed in the gas injector 40 of a plasma apparatus for a 1950 mm×2250 mm substrate. Further, the injection holes 42 over about 60000 ea may be formed in the gas injector 40 of a plasma apparatus for a 2200 mm×2550 mm substrate.
FIGS. 3A and 3B are schematic cross-sectional views showing an injection hole of a gas injector according to the related art. In FIG. 3A, the injection hole 42 includes a gas inlet portion 42a, a nozzle portion 42b, a first diffusing portion 42c and a second diffusing portion 42d having different shapes and different diameters from one another. In FIG. 3B, the injection hole 42 includes a nozzle portion 42b, a first diffusing portion 42c and a second diffusing portion 42d having different shapes and different diameters from one another without a gas inlet portion 42a. 
The nozzle portion 42b may have a diameter of about 0.4 mm to about 0.8 mm, and the gas inlet portion 42a and the first diffusing portion 42c may have a diameter over about 3 mm. Through the nozzle portion 42b having a finite diameter, the reaction gases are uniformly diffused in the buffer space 52 (of FIG. 1) and are uniformly injected into the chamber 10 (of FIG. 1) by increasing a pressure of the reaction gases in an upper portion of the injection hole 42. Accordingly, as a diameter of the nozzle portion 42b decreases, the reaction gases are injected more uniformly.
To obtain the injection hole 42 of FIGS. 3A and 3B, after the nozzle portion 42b is formed in the gas injector 40 (of FIG. 1), the gas inlet portion 42a and the first diffusing portion 42c are sequentially formed at upper and lower portions of the nozzle portion 42b. However, it requires high manufacturing technology to form the nozzle portions 42b over 50000 ea each having a diameter of about 0.4 mm in an aluminum (Al) plate having a thickness of about 50 mm. In addition, when a single nozzle portion 42b is inferiorly formed during the manufacture of the injection holes 42, the gas injector 40 (of FIG. 1) having the inferior nozzle portion 42b cannot be used for a plasma apparatus requiring high accuracy and high uniformity. Accordingly, the gas injector 40 (of FIG. 1) having the inferior nozzle portion 42b should be disused. Accordingly, fabrication cost for the gas injector increases and production period for the gas injector is elongated.